abstract class Animal{
    String sex;
    int age;

    public abstract void bark();
}
class Dog extends Animal{
    String name;
    {
        age = 12;
    }

    @Override
    public void bark() {
        System.out.println(name + "在吃饭");
        System.out.println(age);
    }
}
public class Zoo {
    public static void main(String[] args) {
        Dog dog = new Dog();
        dog.name = "小七";
        dog.bark();
    }
}
